JP3249735B2 - Ink ejecting apparatus and driving method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, your ink jet apparatus
It relates driving method Yobiso.

[0002]

2. Description of the Related Art The non-impact type printing apparatus which has been replacing the conventional impact type printing apparatus and is now expanding its market greatly is the simplest in principle and has a multi-gradation and color printing. An easy-to-use printing apparatus is an ink jet printing apparatus. Above all, the drop-on-demand type, which ejects only ink droplets used for printing, is rapidly spreading due to its good ejection efficiency and low running cost.

The Kaiser type disclosed in Japanese Patent Publication No. 53-12138 as a drop-on-demand type,
Alternatively, a thermal jet type disclosed in Japanese Patent Publication No. 61-59914 is a typical method.
Among them, the former is difficult to miniaturize, and the latter requires a heat resistance of the ink in order to apply high heat to the ink, and each has a very difficult problem.

A new method for simultaneously solving the above-mentioned defects has been proposed in Japanese Patent Application Laid-Open No. 63-247051.
This is a shear mode type using piezoelectric ceramics disclosed in Japanese Patent Application Laid-Open Publication No. H11-157, 1988. As shown in FIG. 6, a shear mode ink jet head 600 includes a bottom wall 601, a top wall 602, and a shear mode actuator wall 60 therebetween.
Consists of three. The actuator wall 603 is connected to the bottom wall 60.
1 and a lower wall 607 that is polarized in the direction of arrow 611, and an upper wall 605 that is bonded to top wall 602 and polarized in the direction of arrow 609. The actuator walls 603 are paired, and the ink flow path 6
13 and the next pair of actuator walls 603
Between them, a space 615 narrower than the ink flow path 613 is formed.

At one end of each ink flow path 613, a nozzle 6
A nozzle plate 617 having an 18 is fixed, and electrodes 619 and 621 are provided on both side surfaces of each actuator wall 603. Each of the electrodes 619 and 621 is covered with an insulating layer (not shown) for insulating the ink. The electrode 619 facing the space 615 is connected to the ground 623.
The electrode 621 provided in the ink flow path 613 is connected to a silicon chip 625 which is an actuator drive circuit. In addition, each ink flow path 613
At the other end, a filler plate 627 having an opening is fixed, and at the other end of each ink flow path 613, a manifold for supplying ink from an ink supply source (not shown) to each ink flow path 613 is provided. A manifold member 628 on which 626 is formed is fixed.

Next, a method for manufacturing the ink jet head 600 will be described. First, the piezoelectric ceramic layer polarized in the direction of the arrow 611 is bonded to the bottom wall 601, and the piezoelectric ceramic layer polarized in the direction of the arrow 609 is bonded to the top wall 602. The thickness of each piezoelectric ceramic layer is equal to the height of the lower wall 607 and the upper wall 605. Next, a parallel groove is formed in the piezoelectric ceramic layer by rotation of a diamond cutting disk or the like to form a lower wall 607 and an upper wall 605. Then, electrodes 619 and 621 are formed on the side surfaces of the lower wall 607 by vacuum evaporation or the like, and the electrodes 619 and 621 are formed.
1 is provided with the insulating layer. Similarly, electrodes 619 and 621 and the insulating layer are provided on the side surface of the upper wall 605.

The ink channel 613 and the space 615 are formed by bonding the zenith of the upper wall 605 and the zenith of the lower wall 607. Next, the nozzle plate 617 in which the nozzle 618 is formed is adhered to one end of the ink flow path 613 and the space 615 so that the nozzle 618 corresponds to the ink flow path 613, and At the other end, electrode 621 and electrode 619 are connected to silicon chip 625 and ground 623. The sealing plate 627 in which the opening is formed is connected to the ink passage 613 by the opening.
The manifold member 628 in which the manifold 626 is formed is adhered to the other end of the ink flow path 613 and the space 615 so as to correspond to the above.
5 is adhered to the other end.

The electrodes 621 of each ink flow path 613
When a voltage is applied by the silicon chip 625 to each of the actuators, each actuator wall 603 undergoes a piezoelectric thickness-shear deformation in a direction to increase the volume of the ink flow path 613. For example, when a voltage V is applied to the electrode 621c of the ink flow path 613c as shown in FIG. 7, an electric field in the directions of arrows 629 and 631 is generated on the actuator wall 603e, and the electric field in the directions of arrows 630 and 632 is generated on the actuator wall 603f. An electric field is generated, and the actuator walls 603e and 603f undergo a piezoelectric thickness shear deformation in a direction to increase the volume of the ink flow path 613c. At this time, the ink flow path 61 including the vicinity of the nozzle 618c
The pressure in 3c decreases. This state is maintained for the one-way propagation time T of the pressure wave in the ink flow path 613. Then
In the meantime, ink is supplied from the manifold 626. Note that T is the time required for the pressure wave in the ink flow path 613 to propagate in the longitudinal direction of the ink flow path 613,
T = L / a is determined by the length L of the ink flow path 613 and the sound velocity a in the ink inside the ink flow path 613. According to the pressure wave propagation theory, the pressure in the ink flow path 613 reverses and changes to a positive pressure just after T time has elapsed from the application of the voltage, but the electrode 621c of the ink flow path 613c is synchronized with this timing. Is returned to 0.

Then, the actuator walls 603e, 60
3f returns to the state before deformation (FIG. 6), and pressure is applied to the ink. At this time, the pressure that has turned positive and the pressure generated when the actuator walls 603e and 603f return to the state before deformation are added, and a relatively high pressure is generated in a portion of the ink flow path 613c near the nozzle 618c. Accordingly, ink droplets are ejected from the nozzle 618c.

Conventionally, this type of ink jet head 60
As shown in FIG. 8, for example, the ink used at 0 ° C. has a viscosity of about 3 mPa · s at 25 ° C.
However, at 10 ° C., about 6 mPa · s, and at 40 ° C., about 2 mPa · s.
The characteristics change greatly with mPa · s and temperature. Due to this change in ink viscosity, the ink droplet ejection speed is lower at low temperatures than at high temperatures, the landing position shift is large, and the print quality is degraded. Therefore, the driving voltage of the inkjet head is changed depending on the ambient temperature in order to suppress a change in the ink droplet ejection speed so that the printing quality is not deteriorated.

[0011]

However, in the driving method of the ink ejecting apparatus having the above-described structure, a complicated voltage variable circuit or two or more power supplies for changing a driving voltage in accordance with a change in ambient temperature. And the cost is high.

According to the present invention, there is provided a low-cost ink ejecting apparatus and an ink jet ejecting apparatus capable of obtaining a good print quality with a small change in the ink droplet ejecting speed due to a change in ambient temperature with only a single driving voltage .
An object of the present invention is to provide a method of driving a Yobiso.

[0013]

In order to achieve this object, according to the first aspect of the present invention, there is provided an ink jet printer in which ink is filled.
An inkjet head having an actuator for changing the volume of the road and the ink flow path is disposed near the front Symbol actuator, by applying the electrical signal the actuator, the pressure to the ink in the ink flow path the an ink jet equipment and a drive circuit for ejecting ink droplets in addition, the inkjet heads
When the temperature of the ink is lower than the predetermined temperature, the first drive waveform including the non-ejection pulse signal for not ejecting the ink droplet and the ejection pulse signal for ejecting the ink droplet is applied to the above-mentioned impulse response.
When the temperature of the jet head is equal to or higher than the predetermined temperature , the second drive waveforms each including a smaller number of pulse signals than the number of pulse signals constituting the first drive waveform are respectively transmitted. It said drive circuit to inject Lee ink droplets with indicia pressure to the actuator.

By driving the ink ejecting apparatus as described above, when the temperature is lower than the predetermined temperature, the number of currents flowing through the drive circuit is increased by the first drive waveform to generate heat, thereby quickly raising the temperature of the actuator. Let it.
When the temperature is equal to or higher than the predetermined temperature, the number of currents flowing through the drive circuit is reduced by the second drive waveform, heat generation is suppressed, and the stable temperature of the actuator is reduced. That is, the time required to reach the stable temperature is shortened, and the stable temperature is lowered. Therefore, the ink droplet ejection speed due to a change in the viscosity of the ink due to a change in the temperature of the actuator has a small change, and good print quality can be obtained.

In the ink ejecting apparatus according to a second aspect, the first
-Injection pulse signal and ejection pulse signal in drive waveforms
And the peak value is the same, and in the second drive
Between the pulse signal and the ejection pulse signal having the first drive waveform.
The crest values are the same. In the ink jet equipment according to claim 3,
The actuator, by applying the pulse signal,
After changing the volume of the ink flow path from the natural state to the increased state, an operation of returning to the natural state is performed again, and the first driving is performed.
The pulse width of the ejection pulse signal in the waveform is
And several times odd one-way propagation time T of a pressure wave in the flow channel to inject <br/> ink droplets, the pulse width of the non-ejection pulse signal, 0.3 T or less, or (N-0 .3) T ~ (N +
With 0.3) T (N is an even number), not ejecting ink droplets Suga flow a current to the drive circuit.

[0016] In the ink jet equipment according to claim 4, wherein the first
Is composed of two pulse signals of the non-ejection pulse signal and the ejection pulse signal, and the second drive waveform is composed of one ejection pulse signal,
The driving frequency can be increased.

[0017] In the ink jet equipment according to claim 5, wherein the first
Is a driving waveform for applying the ejection pulse signal after applying the non-ejection pulse signal, and by adjusting an interval between the non-ejection pulse signal and the ejection pulse signal, ejection is performed by an ejection pulse signal. It is possible to make the speed and volume of the ink droplets appropriate. Claim 6
In the driving method of the ink ejecting apparatus, the ink is filled.
To change the volume of the ink flow path and the ink flow path
Inkjet head having an actuator of
The actuator is disposed in the vicinity of the actuator.
A driving circuit for applying an electric signal to the
In an injection device, an electric signal is supplied to the actuator.
By applying pressure, pressure is applied to the ink in the ink flow path.
Is a driving method for ejecting ink droplets by adding
When the temperature of the inkjet head is lower than a predetermined temperature
Is a non-ejection pulse signal that does not eject ink droplets, and
An ejection pulse signal for ejecting ink droplets.
The driving waveform is changed when the temperature of the inkjet head is a predetermined temperature.
Degrees or more, the pulses constituting the first drive waveform
A second pulse signal having a smaller number of pulse signals than the number of pulse signals.
A drive waveform is applied to each of the actuators to
Ink droplets are ejected. The drive of the ink ejection device according to claim 7.
The dynamic process, wherein the first drive waveform, the non-jetting pulses
Drive to apply the injection pulse signal after applying the signal
It is a waveform.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

The ink jet head 600 of the present embodiment
Comprises a bottom wall 601, a top wall 602, and a shear mode actuator wall 603 therebetween, as in the conventional inkjet head 600 shown in FIG. The actuator wall 603 is adhered to the bottom wall 601 and the arrow 611
It comprises a lower wall 607 polarized in the direction, and an upper wall 605 bonded to the top wall 602 and polarized in the direction of arrow 609. Actuator walls 603 are paired,
An ink flow path 613 is formed in the meantime, and a space 615 narrower than the ink flow path 613 is formed between the next pair of actuator walls 603.

At one end of each ink flow path 613, a nozzle 6
A nozzle plate 617 having an 18 is fixed, and electrodes 619 and 621 are provided on both side surfaces of each actuator wall 603. Each of the electrodes 619 and 621 is covered with an insulating layer (not shown) for insulating the ink. The electrode 619 facing the space 615 is connected to the ground 623.
The electrode 621 provided in the ink flow path 613 is connected to a silicon chip 625 which is an actuator drive circuit. In addition, each ink flow path 613
At the other end, a filler plate 627 having an opening is fixed, and at the other end of each ink flow path 613, a manifold for supplying ink from an ink supply source (not shown) to each ink flow path 613 is provided. A manifold member 628 on which 626 is formed is fixed. The inkjet head 600 and the silicon chip 625 are mounted on a carriage (not shown) that moves along the recording medium.

One example of specific dimensions of the ink jet head 600 is that the length L of the ink flow path 613 is 7.5 mm.
It is. The diameter of the nozzle 618 is 4
0 μm, the diameter on the ink flow channel 613 side is 72 μm, and the length is 1
00 μm. The viscosity at 25 ° C. of the ink used in the experiment was about 3 mPa · s, and the surface tension was 30 mN / m.
The temperature change of the viscosity is about 6 mPa · s at 10 ° C. and about 2 mPa · s at 40 ° C. as shown in FIG. The ratio L / a (= T) between the sound speed a and the above L in the ink in the ink flow path 613 was 8 μsec.

Next, the electrode 6 in the ink flow path 613 of the present invention is used.
FIG. 1 shows the driving waveforms 10 and 20 applied to 21. Second
Is a waveform for suppressing the amount of heat generated by the head and reducing the ejection speed of the ink droplets, and the first drive waveform 20 is for increasing the amount of heat generated by the head and reducing the amount of ink droplets. This is a waveform for increasing the injection speed. The ink is driven using the first drive waveform 20 in a low temperature range where the ink has a high viscosity, for example, 25 ° C. or less, and the second drive waveform 10 is used in a high temperature range where the ink has a low viscosity, for example, 25 ° C. or more. Thus, the temperature of the head and the ink can be quickly shifted from the low temperature range to the high temperature range, and ink droplets can be ejected while maintaining a stable temperature in the high temperature range.

The second drive waveform 10 comprises only a first pulse signal A for ejecting ink droplets, and the peak value (voltage value) of the first pulse signal A is V (for example, 20 V).
It is. The width Wa of the first pulse signal A depends on the ink flow path 6
13 is equal to the one-way propagation time T (L / a) of the pressure wave, that is, 8 μsec.

The first drive waveform 20 comprises a second pulse signal B for not ejecting ink droplets and a third pulse signal C for ejecting ink droplets. The peak value (voltage value) of each of the third pulse signals C is V (for example, 20 V). Second pulse signal B
Is twice the one-way propagation time T (L / a) of the pressure wave in the ink flow path 613, that is, 16 μsec.
The width Wc of the third pulse signal C is equal to the one-way propagation time T of the pressure wave in the ink flow path 613, that is, 8 μsec.

An embodiment of a drive circuit inside the silicon chip 625 for realizing the drive waveforms 10 and 20 will be described with reference to FIGS. The output signals X and Y shown in FIG.
Are signals for setting the voltages applied to the electrodes 619 in the ink flow path 613 to V and 0, respectively. When the output signal X is turned on, a voltage V is generated, and when the output signal Y is turned on, the voltage becomes zero. The capacitor 191 is connected to the ink flow path 61.
3 actuator wall 603 and electrodes 619 and 621 formed on both sides thereof.

The driving circuit is composed of two blocks surrounded by broken lines, each of which is a charging circuit 182 and a discharging circuit 184. When the input signal X is turned on, the transistor Tc conducts, and a voltage of V from the positive power supply 187 to the electrode E of the capacitor 191 via the resistor R120.
For example, 20v is applied. When the input signal Y is turned on, the transistor Tg conducts, and the voltage E of the capacitor 191 is grounded via the resistor R120. First drive waveform 2
FIG. 3 shows timing charts 21 and 22 of the input signals X and Y in the case of 0 and an output voltage waveform 23 of the electrode E.

As shown in the timing chart 21 of the input signal X, the input signal X is normally in an off state, and is turned on at predetermined timings T1 and T3 for injection, and turned off at predetermined timings T2 and T4. . The timing chart 22 of the input signal Y is turned off when the input signal X is on, and turned on when the input signal X is off.
The output waveform 23 at the electrode E at that time is normally 0 V, but the charge to the capacitor 191 is charged at the timing T1, and the voltage V (for example, after the charging time Ta determined by the transistor Tc, the resistor R120, and the capacitor 191) 20
v). During the charging time Ta, the positive power supply 187 supplies the transistor Tc, the resistor R120, and the capacitor 191.
Current flows through

At timing T2, the capacitor 191
Is discharged, and becomes 0 V after a discharge time Tb determined by the transistor Tg, the resistor R120, and the capacitor 191. During the charging time Tb, current flows from the capacitor 191 to the resistor R120 and the transistor Tg.

Subsequently, at timing T3, the capacitor 19
1 is charged, the transistor Tc and the resistor R12
The voltage becomes V (for example, 20 V) after a charging time Ta determined by 0 and the capacitor 191. During the charging time Ta, a current flows from the positive power supply 187 to the transistor Tc, the resistor R120, and the capacitor 191.

At timing T4, the capacitor 191
Is discharged, and becomes 0 V after a discharge time Tb determined by the transistor Tg, the resistor R120, and the capacitor 191. During the charging time Tb, current flows from the capacitor 191 to the resistor R120 and the transistor Tg.

As described above, since the actual drive waveform 23 has a delay of Ta and Tb at the rise and fall, respectively, the second pulse signal B of the first drive waveform 20 at the voltage of 1/2 V (for example, 10 V). Width Wb, third
The timings T1, T2, T3, and T4 are set so that the width Wc of the pulse signal C has a predetermined value. Similarly, the second drive waveform 10 also includes the first pulse signal A
Is set to have a predetermined value.

As described above, in the ink jet head 600 using piezoelectric ceramics, when the piezoelectric ceramics are deformed, that is, when the drive waveform rises and falls, a current flows through the drive circuit. 625 generates heat. In the second drive waveform 10, the current flows twice through the silicon chip 625, and in the first drive waveform 20, the current flows four times through the silicon chip 625.
The heat generation of the silicon chip 625 is larger than the driving waveform 10 of FIG.

Next, an ink ejection test was performed in the case of driving by the driving method of the present embodiment. The ink jet head 60 when the temperature of the ink jet head 600 is 10 ° C. and the second drive waveform 10 and the first drive waveform 20 are continuously driven at a drive voltage of 20 V.
A temperature change of 0 was measured. When the temperature of the inkjet head 600 is lower than 25 ° C., the second drive waveform 1
0 and the temperature of the inkjet head 600 is 2
When the temperature was 5 ° C. or higher, the temperature change of the inkjet head 600 when driven by the first drive waveform 20 was also measured. The result of this test is shown in FIG. When driven by the second drive waveform 10, about 7.5 ° C./min. The temperature of the inkjet head 600 rises at a speed of
It can be seen that the temperature reaches 32 ° C. after 0 seconds and stabilizes. When driven by the first drive waveform 20, about 30 ° C./min.
The temperature of the inkjet head 600 rises at the speed of
It can be seen that the temperature reaches 76 ° C. after 160 seconds and is stabilized. When each drive waveform is used alone, the second drive waveform 1
In the case of 0, the stable temperature is not so high,
There is a problem that the temperature rises slowly and it takes a long time for the temperature to stabilize. In the case of the first drive waveform 20, there is a problem that the stable temperature becomes too high, but the temperature rise is fast.

When the temperature is lower than 25 ° C., the first driving waveform 2
When the second driving waveform 10 is used at a temperature of 0 or 25 ° C. or higher, the temperature of the
After 25 seconds, the temperature reaches 25 ° C, and after 100 seconds, it reaches 32 ° C and stabilizes.
The stable temperature is as low as 32 ° C. Therefore, the ink droplet ejection speed due to a change in the viscosity of the ink due to a change in the temperature of the inkjet head 600 is small, and good print quality can be obtained.

Further, in this embodiment, the first pulse signal A in the second drive waveform 10, the second pulse signal B in the first drive waveform 20, and the third pulse are applied to the electrode 619 of the ink flow path 613. Since the same positive voltage V is applied to all the signals C, only the positive power supply 187 is required as the driving power supply, which is compared with a conventional case using a voltage variable circuit or using two or more power supplies having different voltages. Thus, the control circuit is simplified, and the cost can be reduced.

Further, since the first drive waveform 20 is composed of two pulse signals and the second drive waveform 10 is composed of one pulse signal, the drive frequency can be increased.

The first driving waveform 20 is a driving waveform in which a third pulse signal C for ejecting ink droplets is applied after a second pulse signal B for not ejecting ink droplets is applied. By adjusting the interval between the second pulse signal B and the third pulse signal C, the velocity and volume of the ejected ink droplet can be set to appropriate values.

Next, the results of an experiment performed to determine the appropriate range of the pulse signal width of each of the second drive waveform 10 and the first drive waveform 20 will be described. As an evaluation method, when the ambient temperature was 25 ° C., the width W of the pulse signal was changed, and the ink droplet ejection speed when driven at 20 V and 1 kHz was measured. The result is shown in FIG. From this result, the width Wa of the first pulse signal A and the third pulse signal C
Are 1.0T, 3.0T, 5.0T, and 7.0T.
And that the injection time is an odd multiple of the one-way propagation time T of the pressure wave, a stable injection can be obtained.
Of width Tb of 0.3T or less, 1.7T to 2.3T, 3.7
When T to 4.3T, 5.7T to 6.3T, it can be seen that there is no injection by the second pulse signal B.

Although one embodiment has been described in detail, the present invention is not limited to this embodiment. For example, although the positive power supply 187 is used in the above embodiment, a negative power supply may be used by reversing the polarization directions of 609 and 611 in FIG. The present invention can be implemented in other configurations with various changes and improvements based on the knowledge of those skilled in the art without departing from the scope of the claims.

In this embodiment, the second drive waveform 10
Although the switching between the first drive waveform 20 and the first drive waveform 20 is performed at a boundary of 25 ° C., the present invention is not limited to this. For example, the switching may be performed at 20 ° C.

In this embodiment, the first drive waveform 20
Is composed of two pulse signals, but is not limited thereto. For example, it may be composed of three or four pulse signals. In this case, since the heat generated by the silicon chip 625 is larger than the drive waveform including two pulse signals, the temperature of the actuator can be increased to the predetermined temperature in a shorter time.

Further, the ink jet head 6 of this embodiment
Although 00 has air chambers 615 on both sides of the ink flow path 613, an ink ejecting apparatus having an ink flow path adjacent thereto without providing an air chamber may be used.

In this embodiment, the actuator wall 6
Although the lower wall 03 is composed of the lower wall 607 and the upper wall 605 polarized in opposite directions, the actuator wall may have only the upper or lower part polarized.

In this embodiment, the ink jet head 600 and the silicon chip 625 are mounted on a carriage (not shown). However, a recording apparatus having no carriage, for example, a line head type having a nozzle corresponding to the width of a recording medium is used. In the case of the recording apparatus described above, the silicon chip and the inkjet head may be arranged at a distance where heat generated by the silicon chip is transmitted to the inkjet head.

[0045]

As described above, according to the ink ejecting apparatus of the first aspect and the driving method of the sixth aspect of the present invention, a non-ejection pulse signal that does not eject an ink droplet at a temperature lower than a predetermined temperature ; a first drive waveform having an ejection pulse signal for ejecting ink droplets, a sign to the actuator
Since pressurized to have to inject Lee ink droplets, thereby generating heat by increasing the number of the current flowing through the driving circuit, it is possible to raise the temperature of the actuator quickly. Also in the above predetermined temperature, the pre-Symbol second drive waveform comprising a first small number of pulse signals than the number of pulse signals constituting the drive waveform, to inject Lee ink droplets is applied to the actuator Therefore, the number of times of the current flowing through the drive circuit can be reduced to suppress heat generation, and the stable temperature of the actuator can be reduced. That is, to shorten the time to reach a stable temperature, it is possible to lower the steady-state temperature, due to the temperature change of the actuator, the ink droplet ejection speed change is small due to the viscosity change of the ink, good printing quality Obtainable.

The peak value of each pulse signal is the same.
As a result, it is possible to drive with a single drive power supply, so that the drive circuit is simpler than in the related art, and the cost can be reduced.

According to the third aspect of the present invention, the actuator changes the volume of the ink flow path from a natural state to an increased state by applying the pulse signal, and then returns to the natural state again. And the first drive waveform
The pulse width of the injection pulse signal at, by several times odd one-way propagation time T of a pressure wave in the ink flow path <br/> inside, it is possible to eject ink droplets, the non-ejection pulse When the pulse width of the signal is 0.3T or less, or (N
−0.3) T to (N + 0.3) T, (N
It is an even number), it is not necessary to eject ink droplets by Suga flow a current to the drive circuit.

According to the fourth aspect of the present invention, the first drive waveform is composed of two pulse signals of the non-ejection pulse signal and the ejection pulse signal, and the second drive waveform is one pulse signal. The driving frequency can be increased because the injection pulse signal is composed of the two ejection pulse signals.

An ink jet apparatus according to claim 5 and claim 7.
According to the driving method of ( 1), since the first drive waveform is a drive waveform of applying the ejection pulse signal after applying the non-ejection pulse signal, the interval between the non-ejection pulse signal and the ejection pulse signal is By adjusting, the speed and volume of the ink droplet ejected by the ejection pulse signal can be set to appropriate values.

[Brief description of the drawings]

FIG. 1 is a diagram showing a driving waveform of an inkjet head according to an embodiment of the present invention.

FIG. 2 is a diagram showing a driving circuit of the inkjet head.

FIG. 3 is a diagram showing a timing chart for driving the inkjet head.

FIG. 4 is a diagram showing a result of an experiment in which a driving waveform of the inkjet head is changed.

FIG. 5 is a diagram illustrating the results of an experiment performed to determine an appropriate range of the pulse signal width of the driving waveform of the inkjet head.

FIG. 6 is a view showing a conventional example and an ink jet head according to the present invention.

FIG. 7 is a diagram illustrating the operation of a conventional example and an ink jet head according to the present invention.

FIG. 8 is a diagram illustrating a change in viscosity of the ink according to the related art and the present invention with temperature.

[Explanation of symbols]

 Reference Signs List 10 Second drive waveform 20 First drive waveform 187 Positive power supply 600 Inkjet head 603 Actuator wall 613 Ink flow path 625 Silicon chip

Claims (7)

(57) [Claims] An ink flow path filled with ink and an actuator for changing the volume of the ink flow path are provided.
Ink having an ink jet head is arranged near the front Symbol actuator, by applying the electrical signal conductive to the actuator, and a drive circuit for ejecting ink droplets by applying pressure to the ink in the ink flow path comprising a jet equipment, when the temperature of the ink-jet head is less than a predetermined temperature
The, the non-ejection pulse signal which does not eject ink droplets,
An ejection pulse signal for ejecting ink droplets.
The driving waveform, when the temperature of the ink-jet head is equal to or higher than a predetermined temperature, the second consisting pre Symbol first small number of pulse signals than the number of pulse signals constituting the drive waveform
Ink jet equipment that the drive waveform, each of the driving circuit is characterized in that for ejecting Lee ink droplets to sign addition to the actuator. 2. A non-ejection pallet according to the first drive waveform.
And the ejection pulse signal have the same peak value, and
The pulse signal in the second drive and the first drive wave
The characteristic is that the peak value is the same as the shape of the injection pulse signal
Ink jet equipment according to claim 1,. 3. The actuator performs an operation of changing the volume of the ink flow path from a natural state to an increased state by applying the pulse signal, and then returning the ink flow path to the natural state again,
The pulse width of the ejection pulse signal in the first drive waveform is one-way propagation time T of the pressure wave in the ink flow path .
A multiple of an odd pulse width of the non-ejection pulse signal, 0.3 T or less, or (N-0.3) T~ (N +
Ink jet equipment according to claim 2, characterized in that 0.3) it is T (N is an even number). Wherein said first driving waveform is the result of two pulse signals with non-ejection pulse signal and the ejection pulse signal, the second driving waveform, be comprised of a single jetting pulse signal ink jet equipment according to any of claims 1 to 3, characterized in. Wherein said first driving waveform is any of claims 1-4, characterized in that the driving waveforms for applying the injection pulse signal after applying the non-ejection pulse signal
Ink jet equipment according to any. 6. An ink flow path filled with ink and said ink flow path.
An actuator for changing the volume of the ink flow path
Having an ink jet head and the actuator
Located near and applies an electric signal to the actuator
And a driving circuit for performing the
By applying an electric signal to the actuator,
Pressure on the ink in the ink flow path to
A driving method for ejecting droplets, When the temperature of the inkjet head is lower than a predetermined temperature
Has a non-ejection pulse signal that does not eject ink droplets,
An ejection pulse signal for ejecting ink droplets.
The driving waveform of the ink jet head is adjusted to a predetermined temperature.
When the temperature is equal to or higher than the temperature, the pulses constituting the first drive waveform
A second pulse signal having a smaller number of pulse signals than the number of pulse signals.
Drive waveforms are applied to the actuators, respectively.
Ink ejection device characterized by ejecting ink droplets
Driving method. 7. The non-ejection pulse according to claim 1, wherein:
Drive that applies the ejection pulse signal after the
The ink according to claim 6, wherein the ink has a dynamic waveform.
The driving method of the injection device.